Preparation of polymeric fenofibrate formulations with accelerated drug release: Solvent evaporation versus co-grinding

Construction and characterization of avermectin B2 solid nanodispersion

Poorly water-soluble pesticide compounds are difficult to be formulated as environmentally friendly formulations with high efficacy. For the conventional formulations, more than 50% of pesticides are lost during application due to the decomposition of active ingredient, dust drift and running off. Therefore, there is an urgent need to construct a novel formulation for improving the bioavailability of pesticides. The avermectin B2 solid nanodispersion was developed by self-emulsifying and solidification technology. The average particle size, surface tension and contact angle on cabbage leaves of the solid nanodispersion were 35.3 nm, 36.6 mN/m and 58°, respectively. The toxicities of the nanoformulation against diamondback moths and root-knot nematode were more than 1.7 times that of conventional emulsion in water and water dispersible granule. This investigation demonstrated that for foliage-applied pesticides, the formulation bioavailability had positive correlation with wettability which was negatively correlated with surface tension and contact angle. This study provides an easy and scalable technique to construct the effective and environmentally friendly nanoformulations. The toxicity improvement of the solid nanodispersion will significantly reduce dosage and environmental pollution of pesticide. The clarified relationship between formulation parameters and biological activity will contribute to the design and construction of novel pesticide formulations.

Improving abamectin bioavailability via nanosuspension constructed by wet milling technique

BACKGROUND

Poorly water-soluble and photosensitive pesticide compounds are difficult to be formulated as environmentally friendly formulations with high efficacy. Conventional wettable powder, emulsifiable concentrate and emulsion in water have disadvantages of dust drift, overuse of organic solvent and low efficacy. Therefore, there is an urgent need to construct a novel formulation to improve the bioavailability of pesticides.

RESULTS

An abamectin nanosuspension was developed using a wet-milling method combined with orthogonal experimental design. The average particle sizes of the abamectin nanosuspension measured by dynamic light scattering, scanning electron microscope and transmission electron microscope were 233, 90 and 140 nm, respectively. The zeta potential and sliding angle on cabbage leaves were -36.9 mV and 62°. Retention and anti-photolysis were around 1.5 and 1.6 times those of emulsions in water. Furthermore, the biological activity of the nanosuspension towards diamondback moths was approximately twice that of conventional formulations.

CONCLUSION

This study provides an easy and scalable technique for constructing pesticide nanosuspensions. The preparation and composition of the nanosuspension avoid the use of organic solvents. Application of the highly effective nanoformulation will significantly enhance pesticide efficacy, and reduce the dosage and environmental pollution of the pesticide. © 2019 Society of Chemical Industry.

Screening for new pharmaceutical solid forms using mechanochemistry: A practical guide

Within the pharmaceutical industry, and elsewhere, the screening for new solid forms is a mandatory exercise for both existing and new chemical entities. This contribution focuses on mechanochemistry as a versatile approach for discovering new and alternative solid forms. Whilst a series of recently published extensive reviews exist which focus on mechanistic aspects and potential areas of development, in this review we focus on particular practical aspects of mechanochemistry in order to allow full optimisation of the approach in searches for new solid forms including polymorphs, salts and cocrystals as well as their solvated/hydrated analogues. As a consequence of the apparent experimental simplicity of the method (compared to more traditional protocols e.g. solvent-based methods), the high efficiency and range of conditions available in a mechanochemical screen, mechanochemistry should not be considered simply as an alternative method when other screening methods are not successful, but rather as a key strategy in any fully effective solid form screen providing reduced effort and time as well as the potential of requiring reduced amounts of material.

Development and evaluation of targeting ligands surface modified paclitaxel nanocrystals

To overcome the toxicity of excipient or blank nanoparticles for drug delivery nano-system, the surface modified paclitaxel nanocrystals (PTX-NC) have been developed. PTX-NCs were prepared by nano-precipitation method. The surface of PTX-NCs were modified by grafting with apo-transferrin (Tf) or hyaluronic acid (HA). The physical properties of PTX-NCs were evaluated by field emission scanning electron microscope (FE-SEM), zeta-sizer, zeta-potential, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectrometry. In vitro drug release study was performed in phosphate buffered saline (PBS) with or without 0.5% (w/v) Tween 80 for 24h. Cellular uptake was studied at time intervals of 0.5, 1, and 2h in MCF-7 cells, and cell growth inhibition study was performed for 24h using MCF-7 cells (cancer cells), and HaCaT cells (normal cells). Three different types of PTX-NCs with a mean size of 236.0±100.6nm (PTX-NC), 302.0±152.0nm (Tf-PTX-NC) and 339±180.6nm (HA-PTX-NC) were successfully prepared. The drug release profiles showed 29.1%/6.9% (PTX (pure)), 40.7%/23.9% (PTX-NC), 50.5%/25.1% (Tf-PTX-NC) and 46.8/24.8% (HA-PTX-NC) in PBS with/without 0.5% (w/v) Tween 80 for 24h, respectively. As per the results, the drug release of PTX-NCs showed the faster release as compared to that of PTX (pure). Surface modified PTX-NCs exhibited higher values for cell permeability than unmodified PTX-NC in the cellular uptake study. Surface modified PTX-NCs inhibited the cell growth approximately to 60% in MCF-7 cells, however effect of surface modified PTX-NCs on normal cell line was lower than the PTX-NC and PTX (pure). In conclusion, biological macromolecules (Tf or HA) surface modified PTX-NC enhanced the cellular uptake and the cell growth inhibition.

Scale-up from batch to flow-through wet milling process for injectable depot formulation

Injectable depot formulations are aimed at providing long-term sustained release of a drug into systemic circulation, thus reducing plasma level fluctuations and improving patient compliance. The particle size distribution of the formulation in the form of suspension is a key parameter that controls the release rate. In this work, the process of wet stirred media milling (ball milling) of a poorly water-soluble substance has been investigated with two main aims: (i) to determine the parametric sensitivity of milling kinetics; and (ii) to develop scale-up methodology for process transfer from batch to flow-through arrangement. Ball milling experiments were performed in two types of ball mills, a batch mill with a 30ml maximum working volume, and a flow-through mill with a 250ml maximum working volume. Milling parameters were investigated in detail by methodologies of QbD to map the parametric space. Specifically, the effects of ball size, ball fill level, and rpm on the particle breakage kinetics were systematically investigated at both mills, with an additional parameter (flow-rate) in the case of the flow-through mill. The breakage rate was found to follow power-law kinetics with respect to dimensionless time, with an asymptotic d₅₀ particle size in the range of 200-300nm. In the case of the flow-through mill, the number of theoretical passes through the mill was found to be an important scale-up parameter.